Liquid crystal displays (LCD) based on the twisted nematic (TN) mode is the most common type of flat panel display (FPD). Based on the combination of liquid crystals and TFT arrays, the notebook came up in the beginning of the 1990s, and the development of electronics and materials thereof is continued until now. The prerequisite for liquid crystals is a broad nematic phase range of −40 to 100° C. in order to guarantee the so-called operating temperature range of LCDs. The clearing point of a liquid crystal is the temperature at which the liquid crystal phase vanishes. The clearing point must be at least 10° C. higher than the operating temperature of devices. The liquid crystal molecule can be operated in a display device. After a voltage is applied, the liquid crystal molecule is switched to a direction perpendicular to its original direction due to its inherent dielectric anisotropy. For example, after the positive dielectric anisotropic liquid crystal (utilized in general TN mode or IPS mode devices) is applied a driving voltage, a molecular long axis thereof will be influenced by and parallel to an electric field. Contrary to the positive dielectric anisotropic liquid crystal, after the negative dielectric anisotropic liquid crystal (utilized in VA mode devices) is applied a driving voltage, a molecular long axis thereof will be perpendicular to an electric field.
For achieving the above requirements, several papers and patents disclose liquid crystal molecule designs. However, a novel liquid crystal molecule with a more negative dielectric anisotropy and a higher birefringent index is still desired.